Improved physical activity (PA) and nutrition behaviors in adolescents show great promise to reduce risk of cancers and other disease. Fewer than 20 percent of adolescents meet recommendations for fat or fruits and vegetable consumption, and only 50 percent of adolescent girls and 67 percent of boys meet recommendations for vigorous PA. In this project we will evaluate an integrated clinical and home-based intervention to improve PA and nutrition behaviors in adolescents. PACE+ has 3 integrated components: a computer assessment and action planner; provider counseling and 12 months of extended phone & mail contact. Pilot study results (n=117) demonstrate that PACE+ shows substantial promise in maintaining healthy and/or improving poor nutrition & PA behaviors. We will recruit 768 male and female adolescents age 11 through 15 seen in 6 healthcare settings. Subjects will be randomly assigned within practices to 2 successive one-year "doses" of PACE+ or a comparison condition involving counseling for sun protection behaviors. PACE+ assesses 4 behaviors: 1) dietary fat, 2) fruits & vegetable consumption, 3) moderate PA, and 4) vigorous PA. PACE+ also assesses stage of change and psychosocial mediators of behavior change. PACE+ guides the adolescent to select 1 nutrition and 1 PA target behavior for which they develop action plans to discuss during the provider encounter. The provider endorses or modifies the action plan and encourages participation in the extended phone and mail intervention. Phone counseling, mailed and print materials guide the adolescent to use cognitive & behavioral skills to make changes in target nutrition and PA behaviors. At 6 months (midway through the extended component of PACE+) participants are reassessed and receive stage-appropriate intervention on the remaining 2 diet & PA behaviors. The sun comparison condition has theory-based computer, provider, phone & mail components controlling for attention and other non-specific intervention effects. Primary behavioral outcomes, secondary outcomes, and selected mediators and process variables will be measured prior to the first office visit and at 6, 12, and 24 months. Primary outcomes will be measured using the 7-day physical activity recall and the 3-day food records of fruits, vegetables and fat intake at 12 months. Secondary outcomes include adiposity, fitness, BMI, psychosocial mediators of change, body image, and other measures. This study will be the first to evaluate a combined physical activity and nutrition intervention for youth that revolves around the primary health care setting. The PACE+ intervention is particularly innovative in that 3 components--computer, provider counseling, and an extended home-based intervention--are unified through a common theoretical framework.